1. Field of the Invention
The present invention relates to a magnetic impact device, a power tool having the magnetic impact device and a magnetic impact generator. The present invention further relates to a method for magnetically generating impact motion.
2. Discussion of the Background
Portable power tools used for drilling, fastening and the like are expected to be relatively small and light, yet provide high power to perform the functions. Referring to FIG. 1, the tool is typically driven by an electric motor 110. The rotational motion of the motor 110 is transmitted to a chuck 160 which holds a tool bit 115 by means of an intermediate mechanism 120. The motor 110 is generally small due to restrictions imposed on overall size and weight of the portable power tools. Limited power of the small motor might not be enough to drive the intended load. A hammer type of mechanism 120 is introduced to respond to the need to generate high output torque from a small drive.
Referring to FIG. 2, the hammer type of mechanism 120 is rotated by the motor 110. The hammer type of mechanism 120 includes hammers (120a and 120b). The hammer type of mechanism 120 stores the rotational energy of the motor 110 over a large angle of rotation, for example, half turn (180xc2x0). Then the hammers (120a and 120b) hit the chuck 160 to create an impact torque over a small angle (for example 10xc2x0) of rotation of the chuck 160. In this portable power tool, noise is made when the hammers (120a and 120b) hit the chucks 160.
According to one aspect of the present invention, a magnetic impact device includes at least one chuck, at least one hammer and a driving unit. The at least one hammer is relatively movable with respect to the at least one chuck. One of the at least one hammer and the at least one chuck has at least one magnet. Another of the at least one hammer and the at least one chuck has at least one magnet or magnetic material. The driving unit is configured to move the at least one hammer relatively to the at least one chuck to magnetically generate impact motion of the at least one chuck.
According to another aspect of the present invention, a power tool includes a magnetic impact device. The magnetic impact device includes at least one chuck, at least one hammer and a driving unit. The at least one hammer is relatively movable with respect to the at least one chuck. One of the at least one hammer and the at least one chuck has at least one magnet. Another of the at least one hammer and the at least one chuck has at least one magnet or magnetic material. The driving unit is configured to move the at least one hammer relatively to the at least one chuck to magnetically generate impact motion of the at least one chuck.
According to further aspect of the present invention, a power tool magnetic impact generator includes at least one chuck and at least one hammer. One of the at least one hammer and the at least one chuck has at least one magnet. Another of the at least one hammer and the at least one chuck has at least one magnet or magnetic material. The at least one hammer is configured to be moved relatively to the at least one chuck to magnetically generate impact motion of the at least one chuck.
According to further aspect of the present invention, a method for magnetically generating impact motion includes providing at least one chuck and providing at least one hammer. One of the at least one hammer and the at least one chuck is provided with at least one magnet. Another of the at least one hammer and at least one chuck is provided with at least one magnet or magnetic material. The at least one hammer is moved relatively to the at least one chuck to magnetically generate impact motion of the at least one chuck.